Sheet panel



Aug. 15, 1961 a. A. WILSON 2,996,609

SHEET PANEL Filed July'7, 195a FIG. 1

PIC 12 7 INVENTOR.

SHEET PANEL Bertram Arnold Wilson, 516 G. Daniel sala Bldg,

I Erie, Pa. Filed July 7,1958, Ser. No. 746,717

. 6Claims. (('ll.240 '1 This invention is a panel for light diffusing ceilings and I the like adapted to manufacture from fire resisting sheet Plastic such as Poly inylchloride. v

In a preferred form, designed for light diffusing ceilings, the panel is made of two sheets of transparent or translucent plastic sealed in face to face contact around the periphery. At least one of thesheets has a section dished away from the other sheet with the bottom wall of the dished section dimpled at many points back into contact with the other sheet. By uniting the two' sheets at the pointsof contact, a rigid structure is obtained even though the plastic sheets have a thickness of as little as fifteen mils. The light transmission may be increased without materially affecting the rigidity by punching holes in the bottoms of the dimples within the united areas of the sheets. The rigidity is increased when both sheets are dished away from each other and the dimples of each sheet register and are in contact with each other.

In the accompanying drawing, FIG. 1 is a bottom plan view of a panel such as used in light diffusing ceilings; and FIG. 2 is a fragmentary sectional edge view of the panel.

The panel shown in FIGS. 1 and 2 which is of primary use in light diffusing-ceilings is made from two sheets 1 and 2 of transparent or translucent plastic such as polystyrene or polyvinylchloride, polyvinylchloride being preferred for locations 'where fire resistance is important because it will not support combustion. The sheets are in face to face contact throughout the entire peripheral edges and are integrally united to form an outwardly projecting peripheral flange 3a by which the 'Ipanel may be supported, for example by resting on one of the flanges 3 of a T-shaped joist 4. The manner of support is not critical.

The flange 3a may be trimmed off and the panel supported by having the peripheral edges of its lower face rest on the .supporting structure. Each of the sheets has a section 5 dished away from the plane of its peripheral edge consisting of a side wall 6 adjacent the edge of the sheet and a bottom wall 7 lying in a plane parallel to the edge of the sheet. The bottom wall 7 has formed therein dimples 8 extending back to the plane of the edge of the sheet. These dimples are spaced on the same centers alongcenterlines extending both angularly and crosswise ofthe sheet with the dimples in adjacent crosswise rows in staggered relation to each other to obtain a partial nesting of the dimples. This permits the dimpling of a larger proportion of the area of the bottom wall 7 while still maintaining an adequate wall section of the bottom wall between adjacent dimples as indicated at 9. The side walls of adjacent dimples form hollow light directing ribs as is apparent in FIG. 2. The dimples in the sheets 1 and 2 extend toward and are in register with each other so that when the sheets 1 and 2 are placed in face to face contact with theirdished sections 5 registering with each other as illustrated in FIG. 2, the bottom walls 10 of the dimples are in contact with each other and may easily be united, for example by heat sealing. When viewed from the opposite side, the dimples 8 appear as domes and the bottom walls 10 of the dimples are the crests of the domes.

The center section of the united walls It)v may be punched out within the united area as indicated at 11 to improve the light transmission and also to improve the sound deadening effect as is desirable for ceiling panels.

I The panel is completely sealed around its peripheral edge and around the holes 11 which makes it easy to clean by immersion in a cleaning solution or by other procedures.

The sheets and 2 can have the dished sections 5 and the dimples 8 formed therein easily in a single step by 1 Vacuum forming. The. dimples of round cross section illustrated are preferred because that shape results in the simplest and lowest cost mold. Other cross sectional shapes of dimples may be used.

'After the vacuum forming, each of the sheets 1 and Zhas its rigidity greatly increased even though before forming the sheets are quite limp. The rigidity is further increased by the uniting of the peripheral'edges of the sheets 1 and 2 and is still further increased by the uniting of the bottom walls 10 of the registering opposed dimpless. For the construction shown in FIG. 2 where the sheets I and 2 are of polyvinylchloride fifteen mils thick, the dimples 8 may be approximately /2 inch in diameter and with the centers of any two adjacent dimples 95 of an inch apart, and with the depth of the side walls 6 approximately half the diameter of the dimples. The rigidity is such that the panel may be supported by its edges as shown in FIG. 2 without sagging in panel sizes of two feet by four feet or larger. The rigidity is not appreciably affected by the punching of the inch diameter holes 11 which is desirable not only for increasing the light transmission but also for permitting the flow of water through the holes when the ceiling is installed below a sprinkler system. Although the holes 11 permit direct light transmission, the light diffusing properties are not seriously affected because the holes occupy only a minor fraction of the area. Direct view of the light source can be had only by looking along a line of sight inclined upwardly at greater than 45 degrees from the horizontal. For practical purposes the light source is shielded even though direct view is possible.

It will be noted that the dimples 8 are confined to the bottom wall 7 of the dished portion and that the side walls 6 of the dished portion form a continuous stiffening flange bounding the entire dimpled area. Also, there is a continuous unbroken surface of the bottom wall 7 of the dished portion connecting the lower edges of the side walls 6.

In FIGS. 1 and 2, the dimples are closely packed to provide the maximum light transmission.

What is claimed as new is:

l. A light diffusing ceiling unit for use below a light source comprising a supporting frame and a panel edge "supported by said frame below said light source and comprising a sheet of light transmitting plastic having a dished section with side walls transverse to and bordered by the peripheral edge of the sheet and with a bottom wall spaced from the plane of said peripheral edge, said bottom wall having a plurality of dimples therein spaced from each other and from said side walls and extending back toward said plane with the side walls of adjacent dimples forming hollow light directing ribs, another sheet of the same shape as the first sheet, the two sheets being arranged with the dimples and side walls extending toward and abutting each other, and said sheets being united at the abutting portions of the side walls and at the bottoms of the dimples.

2. The unit of claim 1 having holes extending through the dimples within the united areas whereby the unit is adapted for use below sprinklers.

3. A light diffusing ceiling unit for use below a light source comprising a supporting frame and a panel edge supported by said frame below said light source and Patented Aug. 15, 1961 comprising upper and lower sheets of light transmitting plastic united around their peripheral edges, the lower sheet having a plurality of upwardly extending spaced dimples with the side walls of adjacent dimples forming hollow light directing ribs, the upper sheet having a plurality of downwardly extending spaced dimples opposing the dimples in the lower sheet and with the side walls supported by said frame below said light source and comprising a sheet of light transmitting vinyl plastic havof adjacent dimples forming hollow light directing ribs,

and the bottoms of the dimples in the upper and lower sheets registering with each other and being united and having holes extending through the dimples within the united areas.

4. A light difiusing ceiling unit for use below a light source comprising a supporting frame and a panel edge supported by said frame below said light source and comprising a sheet of light transmitting plastic bordered by a continuous flange transverse to the sheet, the area of the sheet within the flange having a plurality of dimples therein extending transverse to the sheet in the same direction as the flange with the side walls of adjacent dimples forming hollow light directing ribs, and another sheet overlying and united to said flange and the bottoms of the dimples.

5. The unit of claim 4 having holes extending through the dimples and the other sheet united thereto within the united areas.

6. A light difiusing ceiling unit for use below a light source comprising a supporting frame and a panel edge ing a dished section with side walls transverse to and bordered by the peripheral edge of the sheet and with a bottom wall spaced from the plane of said peripheral edge, said bottom wall having a plurality of dimples therein spaced from each other and from said side walls and extending back toward said plane with the side walls of adjacent dimples forming hollow light directing ribs, another sheet of the same shape as the first sheet, the two sheets being arranged with the dimples and side walls extending toward and abutting each other, and said sheets being united at the abutting portions of the side walls and at the bottoms of the dimples.

References Cited in the file of this patent UNITED STATES PATENTS 2,410,744 Powers Nov. 5, 1946 2,429,482 Munters Oct. 21, 1947 2,481,046 Scrulock Sept. 6, 1949 2,710,335 Wong June 7, 1955 2,803,741 Guth Aug. 20, 1957 2,851,390 Chavannes Sept. 9, 1958 2,860,237 Baker et al. Nov. 11, 1958 FOREIGN PATENTS 163,515 Austria July 11, 1949 539,745 Italy Feb. 22, 1956 

